PC, First of all, ALWAYS use a double boiler when heating glycerin, no matter what other fractions it may contain. Second, ALWAYS use slow and low heating techniques when heating glycerin, to reduce the possibility of glycerin decaying to acrolein (extremely toxic). Third, NEVER use an open flame heat source when boiling off alcohol, whether it's in the manufacture of glass soap or anything else.
Whether or not you boiled the inordinate majority of alcohol off is difficult to say. You will need a temperature several more degrees above the boiling point of MeOH than the160* you mentioned to achieve this, 165-170 sustained until all evidence of boiling has ended. It should be asked here if what you are referring to as "glycerin" is recovered neutralized glycerin (from the process where FFAs and catalyst are recovered as well) or the crude glycerin layer prior to catalyst recovery, still containing the FFAs and catalyst. In either event, you will need to calculate backwards what the fractions are of the feedstock. If the feedstock is neutralized recovered glycerin, the two fractions will be H20 and glycerin (after the alcohol has been evaporated). You can approximate the percentage of feedstock purity by graphing the ratio weights of H20/glycerin and comparing the per gallon weight of the feedstock to the graph. From there you can determine where to add or subtract water from other parts of the soap recipe that you are using. If the feedstock you are referring to as glycerin is the un-neutralized crude glycerin layer that settles out of a transesterification reaction, you have an entirely different slew of variables. (If you are using crude glycerin from WVO, it is doubtful that you will be terribly pleased with the resulting fragrance of your finished soap product.) The crude glycerin will have fractions of FFAs, glycerin and caustic (after the alcohol has been evaporated). You can presume that the catalyst fraction is the same as what was initially added to the methanol in the biodiesel process. It will actually be slightly less. You can then use that information to calculate necessary addition or subtraction of catalyst to match the soap recipe's requirements. You can roughly calculate the glycerin fraction to be ~79 milliliters for every liter of oil processed.procedure. The balance of the crude glycerin layer will be FFAs, which can be roughly considered the same as a base oil. (If you want to get "critical," subtract 0.40 ml from the initial volume for every gram of catalyst deemed to be present in the crude glycerin when calculating what fractions of the crude glycerin are FFAs and glycerin.) You will need to balance how much of the crude glycerin layer you add to any soap recipe. The volume will be limited by how much catalyst, base oil and/or glycerin is called for. If you choose to incorporate the use of biodiesel co-products into your soap making, it will be helpful to log the inputs and co-products for each batch and keep the co-products from different batches labeled and separate from each other. This will make these crude forms of back measuring considerably more accurate than just "guesswork," yielding more consistent results in your soap manufacturing. Todd Swearingen ----- Original Message ----- From: pcooke04102 <[EMAIL PROTECTED]> To: <biofuel@yahoogroups.com> Sent: Monday, August 26, 2002 9:00 AM Subject: [biofuel] boiling glycerine/soap > Here is a qustion for soap makers. I am trying to make soap out of > the waste glycerine. I boiled 2 liters glycerine at 160 degrees F for > about 15 minutes. Is this enough time to evaporate all the methanol > out? How do you know when its been evaporated. > I then combined 50 grams of lye/liter of glycerine when both were at > temps around 100 degrees F and poured into the bottom of a plastic > jug. Looks like I have round disk of soap. I think I'll try adding > fragrance to the next batch to see if its workable, just wondering > about the methanol being gone-which I'm assuming it is. Any comments > or suggestions? Thanks in advance-PC > > > > Yahoo! Groups Sponsor > ADVERTISEMENT > > > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Biofuels list archives: > http://archive.nnytech.net/ > > Please do NOT send Unsubscribe messages to the list address. > To unsubscribe, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. > > ------------------------ Yahoo! Groups Sponsor ---------------------~--> 4 DVDs Free +s&p Join Now http://us.click.yahoo.com/pt6YBB/NXiEAA/mG3HAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/ Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
